Theoretical study of magnetic excitations in Ni/sub 3/Al

Conference · Wed Jan 01 00:00:00 EST 1986

OSTI ID:5230642

Cooke, J F; Kuebler, J; Liu, S H

Inelastic neutron scattering studies of the transition metal alloy Ni/sub 3/Al have revealed highly unusual spin wave behavior. Spin waves have been observed in a small region around the Brillouin zone center (q approx. = 0). Results from calculations of the inelastic neutron scattering cross section based on itinerant electron theory for Ni/sub 3/Al have led to a relatively simple explanation of this phenomenon. These calculations were carried out using a generalization of the theory and numerical techniques used successfully in the study of the transition metal ferromagnets nickel and iron. To our knowledge, this is the first calculation of this type for an alloy system. The band structure was generated using the augmented spherical-wave method. The calculations yield the well-defined Goldstone mode (spin wave) at q = 0 which must exist in any ferromagnetic material because of the broken symmetry. No spin-wave peaks were found for the smallest calculable non-zero momentum transfer, in agreement with experiment. The reason is simply that the spin wave runs immediately into a region of high density of Stoner excitations (single-particle spin-flip excitations) as q is increased from zero. This high density of Stoner excitations lies very low in both energy and wave vector because the magnetic moment and corresponding spin-splitting energy for Ni/sub 3/Al are quite small; about an order of magnitude smaller than those for nickel. This system, therefore, represents the extreme limiting case of the itinerant electron theory prediction of spin waves disappearing into the Stoner continuum. 4 refs., 2 figs.

• Research Organization: Oak Ridge National Lab., TN (USA). Solid State Div.
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5230642
• Report Number(s): CONF-861111-1; ON: DE86015920
• Resource Relation: Conference: Conference on magnetism and magnetic materials, Baltimore, MD, USA, 17 Nov 1986
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
NICKEL BASE ALLOYS
MAGNETIC PROPERTIES
ALUMINIUM ALLOYS
NEUTRON REACTIONS
SPIN WAVES
ALLOYS
BARYON REACTIONS
HADRON REACTIONS
NICKEL ALLOYS
NUCLEAR REACTIONS
NUCLEON REACTIONS
PHYSICAL PROPERTIES
360104* - Metals & Alloys- Physical Properties
656000 - Condensed Matter Physics